A new host record for Candidatus Phytoplasma cynodontis (16Sr XIV‐A) associated with phyllody and fasciation of linseed (Linum usitatissimum) from India. (27th September 2021)

• Record Type: Journal Article
• Authors: Ajithkumar, K.; Savitha, A.S.; Mahadevakumar, S.; Sreenivasa, M.Y.; Naik, M.K.; Rajanna, B.; Sathyanarayana, R.; Singh, P.K.
• Is Part Of: Letters in applied microbiology. Volume 73:Number 5(2021)
• Page Start: 672
• Page End: 681
• Publication Date: 2021-09-27
• Subjects: linseed -- molecular detection -- new disease report -- phytoplasma; Microbiology -- Periodicals; 660.62
• DOI: 10.1111/lam.13561
• Languages: English
• ISSNs: 0266-8254

Abstract

Abstract: Linseed commonly called as flaxseed ( Linum usitatissimum Linn.) is an important oilseed crop cultivated widely in Northern parts of Karnataka. During, 2019 (January–February), a characteristic disease was noticed with symptoms that resembled phytoplasma or like disease symptoms. The incidence was ranged from 6·5 to 16·5% in the experimental station of Raichur Agricultural University. The typical symptoms observed were virescence of floral parts, fasciation of the inflorescence axis, phyllody, stunted and flattened stem with reduced leaves. Symptomatic and healthy samples were collected and processed for molecular detection of phytoplasma. Total DNA was isolated from four infected plants and two healthy plants. The 16S rDNA region was amplified using P1/P7 followed by R16F2n/R16R2 primer pair which showed the amplification of expected amplicon size from all four infected samples. Furthermore, the SecA gene was amplified using SecA1/SecA3 primers. The PCR amplified products were subjected for direct sequencing from both directions and the consensus sequences were obtained and nBLAST search analysis revealed that the 16Sr RNA and SecA sequences were sharing maximum similarity (100%) with the reference sequence of Ca . P. cynodontis. The sequences were analysed phylogenetically by constructing a Phylogram independently by NJ method along with reference sequence of 16S rRNA region and SecA region retrieved from GenBank database showed that the phytoplasma sequence from linseed phyllody of the present study placed in a distinct clade along with reference sequence of " Ca . P. cynodontis" thus confirming the identity phylogenetically. Furthermore, iPhyClassifier and virtual RFLP proved that the phytoplasma belonged to 16SrXIV (subgroup A) phytoplasma. Previously linseed is known to be associated with 16SrII‐D phytoplasma but the association of the 16SrXIV‐A group of phytoplasma is not reported so far. Therefore, this is the new host record for Ca . P. cynodontis (16SrXIV‐A) phytoplasma associated with linseed stem fasciation, phyllody from India. Abstract : Significance and Impact of the Study: A characteristic phyllody and fasciation disease caused likely by phytoplasma on linseed from India has been investigated in the present study. The pathogen has been identified based on the molecular identification followed by sequence analysis of 16Sr RNA region and SecA gene and their phylogenetic analysis. Virtual RFLP analysis and Candidatus Phytoplasma species assignment by iPhyClassifier confirmed the identity of the associated phytoplasma as Ca . Phytoplasma cynodontis of group 16Sr XIV‐A. This is the first report of Ca . Phytoplasma cynodontis 16Sr XIV‐A group with linseed phyllody and fasciation from India.